/* $Header: /roq/tiff/tif_compress.c 1     11/02/99 4:39p Zaphod $ */



/*

 * Copyright (c) 1988-1996 Sam Leffler

 * Copyright (c) 1991-1996 Silicon Graphics, Inc.

 *

 * Permission to use, copy, modify, distribute, and sell this software and 

 * its documentation for any purpose is hereby granted without fee, provided

 * that (i) the above copyright notices and this permission notice appear in

 * all copies of the software and related documentation, and (ii) the names of

 * Sam Leffler and Silicon Graphics may not be used in any advertising or

 * publicity relating to the software without the specific, prior written

 * permission of Sam Leffler and Silicon Graphics.

 * 

 * THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF ANY KIND, 

 * EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY 

 * WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.  

 * 

 * IN NO EVENT SHALL SAM LEFFLER OR SILICON GRAPHICS BE LIABLE FOR

 * ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND,

 * OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,

 * WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF 

 * LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE 

 * OF THIS SOFTWARE.

 */



/*

 * TIFF Library

 *

 * Compression Scheme Configuration Support.

 */

#include "tiffiop.h"



static int

TIFFNoEncode(TIFF* tif, char* method)

{

	const TIFFCodec* c = TIFFFindCODEC(tif->tif_dir.td_compression);



	if (c)

		TIFFError(tif->tif_name, "%s %s encoding is not implemented",

		    c->name, method);

	else

		TIFFError(tif->tif_name,

		    "Compression scheme %u %s encoding is not implemented",

		    tif->tif_dir.td_compression, method);

	return (-1);

}



int

_TIFFNoRowEncode(TIFF* tif, tidata_t pp, tsize_t cc, tsample_t s)

{

	(void) pp; (void) cc; (void) s;

	return (TIFFNoEncode(tif, "scanline"));

}



int

_TIFFNoStripEncode(TIFF* tif, tidata_t pp, tsize_t cc, tsample_t s)

{

	(void) pp; (void) cc; (void) s;

	return (TIFFNoEncode(tif, "strip"));

}



int

_TIFFNoTileEncode(TIFF* tif, tidata_t pp, tsize_t cc, tsample_t s)

{

	(void) pp; (void) cc; (void) s;

	return (TIFFNoEncode(tif, "tile"));

}



static int

TIFFNoDecode(TIFF* tif, char* method)

{

	const TIFFCodec* c = TIFFFindCODEC(tif->tif_dir.td_compression);



	if (c)

		TIFFError(tif->tif_name, "%s %s decoding is not implemented",

		    c->name, method);

	else

		TIFFError(tif->tif_name,

		    "Compression scheme %u %s decoding is not implemented",

		    tif->tif_dir.td_compression, method);

	return (-1);

}



int

_TIFFNoRowDecode(TIFF* tif, tidata_t pp, tsize_t cc, tsample_t s)

{

	(void) pp; (void) cc; (void) s;

	return (TIFFNoDecode(tif, "scanline"));

}



int

_TIFFNoStripDecode(TIFF* tif, tidata_t pp, tsize_t cc, tsample_t s)

{

	(void) pp; (void) cc; (void) s;

	return (TIFFNoDecode(tif, "strip"));

}



int

_TIFFNoTileDecode(TIFF* tif, tidata_t pp, tsize_t cc, tsample_t s)

{

	(void) pp; (void) cc; (void) s;

	return (TIFFNoDecode(tif, "tile"));

}



int

_TIFFNoSeek(TIFF* tif, uint32 off)

{

	(void) off;

	TIFFError(tif->tif_name,

	    "Compression algorithm does not support random access");

	return (0);

}



int

_TIFFNoPreCode(TIFF* tif, tsample_t s)

{

	(void) tif; (void) s;

	return (1);

}



static int _TIFFtrue(TIFF* tif) { (void) tif; return (1); }

static void _TIFFvoid(TIFF* tif) { (void) tif; }



int

TIFFSetCompressionScheme(TIFF* tif, int scheme)

{

	const TIFFCodec *c = TIFFFindCODEC(scheme);



	tif->tif_setupdecode = _TIFFtrue;

	tif->tif_predecode = _TIFFNoPreCode;

	tif->tif_decoderow = _TIFFNoRowDecode;

	tif->tif_decodestrip = _TIFFNoStripDecode;

	tif->tif_decodetile = _TIFFNoTileDecode;

	tif->tif_setupencode = _TIFFtrue;

	tif->tif_preencode = _TIFFNoPreCode;

	tif->tif_postencode = _TIFFtrue;

	tif->tif_encoderow = _TIFFNoRowEncode;

	tif->tif_encodestrip = _TIFFNoStripEncode;

	tif->tif_encodetile = _TIFFNoTileEncode;

	tif->tif_close = _TIFFvoid;

	tif->tif_seek = _TIFFNoSeek;

	tif->tif_cleanup = _TIFFvoid;

	tif->tif_defstripsize = _TIFFDefaultStripSize;

	tif->tif_deftilesize = _TIFFDefaultTileSize;

	tif->tif_flags &= ~TIFF_NOBITREV;

	/*

	 * Don't treat an unknown compression scheme as an error.

	 * This permits applications to open files with data that

	 * the library does not have builtin support for, but which

	 * may still be meaningful.

	 */

	return (c ? (*c->init)(tif, scheme) : 1);

}



/*

 * Other compression schemes may be registered.  Registered

 * schemes can also override the builtin versions provided

 * by this library.

 */

typedef struct _codec {

	struct _codec*	next;

	TIFFCodec*	info;

} codec_t;

static	codec_t* registeredCODECS = NULL;



const TIFFCodec*

TIFFFindCODEC(uint16 scheme)

{

	const TIFFCodec* c;

	codec_t* cd;



	for (cd = registeredCODECS; cd; cd = cd->next)

		if (cd->info->scheme == scheme)

			return ((const TIFFCodec*) cd->info);

	for (c = _TIFFBuiltinCODECS; c->name; c++)

		if (c->scheme == scheme)

			return (c);

	return ((const TIFFCodec*) 0);

}



TIFFCodec*

TIFFRegisterCODEC(uint16 scheme, const char* name, TIFFInitMethod init)

{

	codec_t* cd = (codec_t*)

	    _TIFFmalloc(sizeof (codec_t) + sizeof (TIFFCodec) + strlen(name)+1);



	if (cd != NULL) {

		cd->info = (TIFFCodec*) ((tidata_t) cd + sizeof (codec_t));

		cd->info->name = (char*)

		    ((tidata_t) cd->info + sizeof (TIFFCodec));

		strcpy(cd->info->name, name);

		cd->info->scheme = scheme;

		cd->info->init = init;

		cd->next = registeredCODECS;

		registeredCODECS = cd;

	} else

		TIFFError("TIFFRegisterCODEC",

		    "No space to register compression scheme %s", name);

	return (cd->info);

}



void

TIFFUnRegisterCODEC(TIFFCodec* c)

{

	codec_t* cd;

	codec_t** pcd;



	for (pcd = &registeredCODECS; (cd = *pcd); pcd = &cd->next)

		if (cd->info == c) {

			*pcd = cd->next;

			_TIFFfree(cd);

			return;

		}

	TIFFError("TIFFUnRegisterCODEC",

	    "Cannot remove compression scheme %s; not registered", c->name);

}

